RESUMO
Cancer cells must overcome anoikis (detachment-induced death) to successfully metastasize. Using proteomic screens, we found that distinct oncoproteins upregulate IL1 receptor accessory protein (IL1RAP) to suppress anoikis. IL1RAP is directly induced by oncogenic fusions of Ewing sarcoma, a highly metastatic childhood sarcoma. IL1RAP inactivation triggers anoikis and impedes metastatic dissemination of Ewing sarcoma cells. Mechanistically, IL1RAP binds the cell-surface system Xc - transporter to enhance exogenous cystine uptake, thereby replenishing cysteine and the glutathione antioxidant. Under cystine depletion, IL1RAP induces cystathionine gamma lyase (CTH) to activate the transsulfuration pathway for de novo cysteine synthesis. Therefore, IL1RAP maintains cyst(e)ine and glutathione pools, which are vital for redox homeostasis and anoikis resistance. IL1RAP is minimally expressed in pediatric and adult normal tissues, and human anti-IL1RAP antibodies induce potent antibody-dependent cellular cytotoxicity of Ewing sarcoma cells. Therefore, we define IL1RAP as a new cell-surface target in Ewing sarcoma, which is potentially exploitable for immunotherapy. SIGNIFICANCE: Here, we identify cell-surface protein IL1RAP as a key driver of metastasis in Ewing sarcoma, a highly aggressive childhood sarcoma. Minimal expression in pediatric and adult normal tissues nominates IL1RAP as a promising target for immunotherapy.See related commentary by Yoon and DeNicola, p. 2679.This article is highlighted in the In This Issue feature, p. 2659.
Assuntos
Anoikis , Proteína Acessória do Receptor de Interleucina-1 , Sarcoma de Ewing , Adulto , Linhagem Celular Tumoral , Criança , Humanos , Proteômica , Receptores de Interleucina-1 , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologiaRESUMO
Alveolar rhabdomyosarcoma (ARMS) has a much poorer prognosis than the more common embryonal subtype. Most ARMS tumors characteristically possess a specific genomic translocation between the genes of PAX3/7 and FOXO1 (FKHR), which forms fusion proteins possessing the DNA binding domains of PAX3/7 and the more transcriptionally potent transactivation domain of FOXO1. We have shown that the proapoptotic BH3-only family member Noxa is upregulated by the PAX3-FOXO1 fusion transcription factor in a p53-independent manner. The increased expression of Noxa renders PAX3-FOXO1-expressing cells more susceptible to apoptosis induced by a γ-secretase inhibitor (GSI1, Z-LLNle-CHO), the proteasome inhibitor bortezomib, and BH3 mimetic ABT-737. Apoptosis in response to bortezomib can be overcome by shRNA knockdown of Noxa. In vivo treatment with bortezomib reduced the growth of tumors derived from a PAX3-FOXO1-expressing primary myoblast tumor model and RH41 xenografts. We therefore demonstrate that PAX3-FOXO1 up-regulation of Noxa represents an unanticipated aspect of ARMS tumor biology that creates a therapeutic window to allow induction of apoptosis in ARMS cells.
Assuntos
Apoptose/genética , Regulação Neoplásica da Expressão Gênica , Proteínas de Fusão Oncogênica/genética , Fatores de Transcrição Box Pareados/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Rabdomiossarcoma Alveolar/genética , Animais , Compostos de Bifenilo/farmacologia , Ácidos Borônicos/administração & dosagem , Ácidos Borônicos/farmacologia , Bortezomib , Linhagem Celular Tumoral , Modelos Animais de Doenças , Humanos , Camundongos , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Nitrofenóis/farmacologia , Oligopeptídeos/farmacologia , Piperazinas/farmacologia , Pirazinas/administração & dosagem , Pirazinas/farmacologia , Rabdomiossarcoma Alveolar/mortalidade , Rabdomiossarcoma Alveolar/patologia , Sulfonamidas/farmacologia , Carga Tumoral/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
To obtain the large amount of T cells required for adoptive immunotherapy in a clinical setting, T-cell lifespan extension by human telomerase reverse transcriptase (hTERT) transduction is of particular interest. However, constitutive expression of hTERT is associated with malignant transformation and thus warrants a detailed evaluation of the safety of hTERT-transduced T cells before clinical application. In view of this, we performed an extensive cytogenetic analysis of hTERT-transduced MART-1 (melanoma antigen recognized by T cell 1)-and human papillomavirus type 16 (HPV16) E7-specific human CD8+ cytotoxic T lymphocytes (CTLs), reactive against melanoma and cervical carcinoma, respectively. Our results, obtained by (spectral) karyotyping and array comparative genomic hybridization, showed the development of minor chromosomal aberrations in an hTERT-transduced MART-1-specific CTL clone, whereas severe clonal aberrations were detected in an hTERT-transduced HPV16 E7-specific CTL clone. Furthermore, hTERT transduction did not protect CTLs from immunosenescence, because the HPV16 E7-specific, hTERT-transduced CTL clone showed a decreased functional activity on prolonged culture. Although the general frequency of major chromosomal aberrations in hTERT-transduced CTLs and the in vivo significance of our observations remain still unclear at this point, the currently available data suggest that clinical application of hTERT-transduced CTLs should proceed with caution.